Endogenous Modulation of Cochlear Injury

描述（申请人提供）：顺铂是一种有效的化疗药物，广泛用于治疗恶性肿瘤。耳毒性等副作用会影响癌症幸存者的生活质量。顺铂增加耳蜗中活性氧（ROS）的形成。NADPH氧化酶的独特异构体，NOX-3，存在于大鼠耳蜗。这种酶会产生超氧化物自由基，损害外毛细胞（ohc），导致听力丧失。活性氧可以激活保护或有害的耳蜗基因。保护分子可能包括一种新的蛋白质，肾损伤分子(KIM)-1。它是由顺铂引起的。该分子可促进近端小管细胞的修复和再生。我们的实验室是第一个在耳蜗中和顺铂诱导下发现KIM-1的实验室。ROS可能上调KIM-1。目前尚不清楚这种蛋白是否能保护耳蜗免受顺铂的影响。顺铂引起的ROS也可能增加潜在有害的瞬时受体-潜在香草样蛋白1受体（TRPV1）的表达。一氧化氮-3和TRPV1的激活可能会破坏耳蜗抗氧化防御，导致细胞死亡。本应用中的实验旨在更精确地定义顺铂耳毒性的机制，以便找到最小化毒性的方法。拟议的研究将利用耳蜗细胞系（UB/OC-1）和大鼠的平行研究来解决三个具体目标：1)研究顺铂在耳蜗中激活NOX-3的机制；2)确定KIM-1的表达是否对顺铂耳毒性具有保护作用，并确定其诱导的潜在机制；3)研究TRPV1是否参与顺铂耳毒性并确定其诱导机制。在目的1中，我们将在圆窗（RW）上系统地给予抗氧化剂硫辛酸或短干扰rna (sirna)，以阻断顺铂对NOX-3的激活。在目标2中，我们将使用信号分子抑制剂的RW应用来观察它们是否参与KIM-1诱导；和RW应用siRNA对KIM-1观察顺铂耳毒性是否增加。在目的3中，我们将研究TRPV1拮抗剂capsazepine是否对顺铂耳毒性有保护作用。我们还将研究RW给药siRNA对TRPV1的影响，看看这是否能防止顺铂耳毒性。本研究可为顺铂耳毒性机制的研究和改善顺铂耳毒性的治疗提供新的思路。在接受顺铂治疗的癌症患者中，有很大一部分人会导致听力丧失。如果能找到一种治疗方法，既能防止听力丧失，又不会干扰顺铂的抗癌效果，这对癌症幸存者来说将是非常有益的。本研究旨在发现新的潜在治疗方法，以减少顺铂治疗癌症导致的听力损失的副作用。在接受顺铂治疗的癌症患者中，有很大一部分人会导致听力丧失。

DESCRIPTION (provided by applicant): Cisplatin is a potent chemotherapeutic agent widely used to treat malignant neoplasms. Side effects, like ototoxicity compromise the quality of life of cancer survivors. Cisplatin increases formation of reactive oxygen species (ROS) in the cochlea. A unique isoform of NADPH oxidase, NOX-3, is present in rat cochlea. This enzyme generates superoxide radicals that can damage outer hair cells (OHCs), leading to hearing loss. ROS can activate cochlear genes that may be protective or harmful. Protective molecules may include a novel protein, kidney injury molecule (KIM)-1. It is induced in kidney by cisplatin. This molecule may enhance repair and regeneration of proximal tubule cells. Our laboratory was the first to show KIM-1 in the cochlea and its induction by cisplatin. ROS may up-regulate KIM-1. It is unknown whether this protein protects the cochlea from cisplatin. ROS resulting from cisplatin may also increase expression of potentially harmful transient receptor potential vanilloid 1 receptors (TRPV1). Activation of NOX-3 and TRPV1 may overwhelm cochlear antioxidant defenses, leading to cell death. Experiments in this application seek to more precisely define mechanisms of cisplatin ototoxicity in order to find ways to minimize toxicity. Studies proposed will utilize a cochlear cell line (UB/OC-1) and parallel studies in rats to address three specific aims to: 1) investigate mechanisms of NOX-3 activation by cisplatin in the cochlea; 2) determine whether expression of KIM-1 confers protection against cisplatin ototoxicity and to determine potential mechanisms of its induction; and 3) study whether TRPV1 contributes to cisplatin ototoxicity and to determine mechanisms of its induction. For aim 1, we will administer systemically the antioxidant lipoic acid or short-interfering RNAs (siRNAs) on the round window (RW) to block activation of NOX-3 by cisplatin. In aim 2, we will use RW application of inhibitors of signaling molecules to see if they are involved in KIM-1 induction; and RW application of siRNA for KIM-1 to see if cisplatin ototoxicity increases. For aim 3, we will investigate whether RW application of the TRPV1 antagonist, capsazepine, protects against cisplatin ototoxicity. We will also examine effects of RW administration of siRNA against TRPV1 to see whether this prevents cisplatin ototoxicity. This research could provide new insights into mechanisms of cisplatin ototoxicity and novel therapeutic approaches to ameliorate cisplatin ototoxicity. Cisplatin causes hearing loss in a large percentage of cancer patients who receive this drug to cure their cancer. It would be of great benefit to cancer survivors if a treatment could be discovered that would prevent hearing loss without interfering with the cancer killing effects of cisplatin. This research seeks to discover new potential treatments to reduce the side effect of hearing loss resulting from the treatment of cancer with the drug cisplatin. Cisplatin causes hearing loss in a large percentage of cancer patients who receive this drug to cure their cancer.